An upper and lower space of an elevator shaft must be equipped with an adequate safety space. This is the case also in so called machine-room-less elevators having elevator drive and other serviceable components mounted inside elevator shaft.
Sufficient upper and lower space is protecting maintenance personnel during maintenance operations. It additionally protects unauthorized intruders, for example for being compressed against the elevator shaft.
The protecting space can, subject to certain conditions, be implemented by a technical safety device instead of a fixed pithole at the bottom of the shaft or a fixed protection room at the top of the shaft. However, an operation of the safety device should be ensured and secured. For example, that the safety device is not jammed, or that it is in a correct position.
A safety device for establishing a temporary safety space in elevator shaft is known from international publication no. WO 2010/122211 A1. This safety device may be implemented with relays, for example.
Publications U.S. Pat. No. 5,727,657A, DE 102005060839A1, JPH09278307A discuss information that can be regarded as useful for understanding the background of the invention.
The present invention is targeted to an improvement for such a safety device.